aspects-js

中文

Use aspect in node js

Just install by npm

$ npm install --save aspects-js

You need require aspects-js at first of entry js file

require('aspects-js');

Add a js file to write an aspect. First, you should require class Aspect from aspects-js.

//file: testAspect.js
const { Aspect } = require('aspects-js');

Secondly, you should declare a class extends Aspect and implements property pointcut and functions for join point.

//file: testAspect.js
class TestAspect extends Aspect {
    get pointcut() { return '*.do*()' },
    before() { console.log('this is for before join point') },
    after() { console.log('this is for after join point') }
}

Then, you should exports an instance of your class which is extends Aspect

//file: testAspect.js
module.exports = new TestAspect();

At last, require your aspects at entry.js file

//file: entry.js
require('./testAspect.js');

Now, all classes when you required will be cut by all your aspects.

interface Aspect {
    readonly pointcut: Pointcut | string | ((joinPoint: JoinPoint) => boolean);
    readonly order: number;

    after(joinPoint: JoinPoint, result: any, error: Error);
    afterReturn(joinPoint: JoinPoint, result: any): any;
    afterThrow(joinPoint: JoinPoint, error: Error): void;
    before(joinPoint: JoinPoint):void;
    around(joinPoint: JoinPoint): any;
}

class JoinPoint {
    readonly type: Class;
    readonly fun: Function;
    readonly thisArg: any;
    readonly target: any;
    readonly args: any[];

    proceed(...args: any[]): any;
}

class Pointcut {
    constructor(pointcut: string);

    matches(joinPoint: JoinPoint): boolean;
}

"ClassName.FunctionName()"

"execution(ClassName.FunctionName())"

"within(ClassName)"

"FunctionName(..)"
"FunctionName(Type1,Type2)"
"FunctionName(Type1,..,Type2)"

"*Service.do*()"

Match all methods which's a name is start with do and in classes which's a name is end with Service

"you?.do?()"

"within(Test1+Test2)"

Just match all methods in classes which's a name is Test1 or Test2

"within(Test1)|within(Test2)"

Just match all methods in classes which's a name is Test1 or Test2

"within(Test1)&abc"

Just match method abc in class Test1

"!within(Test)"

match all methods except the methods in class Test

Increase the priority of expressions

"abc()"
"abc(..)"

Match all methods which's a name is abc

"abc(Type1)"

Match all methods which's a name is abc and has one argument that instance of class Type1

"*(Type1,Type2)"

Match all methods which has two arguments that then first one is instance of class Type1 and the second one is instance of class Type2

"Test.abc()"

Match the method abc of class Test

Match none or multiple arguments

The Higher precedence when the value is lower

support function for pointcut add property order for class Aspects

use AST for pointcut